Appendix 2: Imperial Fleet Vessels
Literally hundreds of classes of ships form the Imperial Fleet, but this document will concentrate only on those that were part of the 342nd Battle Squadron and 501st Transport Flotilla.
Notes on the entries below:
1. Standard tonnage includes all parasite craft, full loads of fuel, munitions, and provisions; full load adds the maximum capacity of all cargo holds (typically an Imperial warship carries 15-20% of the maximum capacity in the form of spare parts and emergency relief supplies—only rarely are these ships forced to utilize their full capacity, with the notable exception of assault transports and dedicated naval stores ships).
2. Hanger decks are normally located on the dorsal surface of the warship, inboard of the secondary battery (see number 6 below). With the exception of the main sensor tower, these facilities are often the highest point on a ship’s hull. The recovery deck is approached from the stern of the ship, and is open to the vacuum of space during recovery operations. Once all craft are recovered, hatches seal the deck and the area is repressurized; elevators are then used to transport the small craft down one deck to the main hanger bay, where they are stored. Imperial ships contain between six and twenty-four launch tubes divided among the port and starboard sides, each of which is capable of launching a single fighter—shuttles are normally launched from the main recovery deck. Typically, a warship retains six fighters on Alert-5 status (ready for launch within five minutes of sounding an alert, although vessels expecting combat tend to have already spotted a full load of fighters within the launch bays, reducing the time to less than 30 seconds from alert to launch. It normally takes between five and ten minutes to spot subsequent fighters after those first craft have been launched (although some highly trained and motivated deck gangs have reportedly reduced this to as low as three minutes).
3. Plasma cannons use a physical cartridge (or shell), which is loaded within the weapon itself. The shell contains a mixture of various chemicals and high-energy isotopes which ignite upon being subjected to massive amounts of electrical energy; the casing is vaporized upon ignition. Light plasma bolts (35mm-50mm) have an explosive yield of between one hundred twenty-five kilograms and three hundred fifty kilograms of conventional high explosive and are mounted extensively on warships as secondaries, an intermediate dual-purpose battery that has a limited range, but can be used against fighters, missiles, shuttles, and capital ships alike. True capital scale plasma cannons fire plasma bolts ranging in caliber from 8cm on the smallest armed escorts, corvettes, frigates, and destroyers to the massive 42cm, 45cm, and 48cm main guns found aboard heavy dreadnoughts. These weapons have yields measuring in dozens of kilotons—hundreds of kilotons for the heavier bolts (the largest plasma cannon ever deployed on active duty by the Imperial Fleet are the 48cm main guns of the Victory class battleships, with a yield of 275 kilotons—in contrast, the 45s of the Washingtons and Levithans are rated at 250 kilotons, while the 26s found aboard Gladiator class cruisers have a yield of just 120-kt and the 16s of the Alexander class Destroyers carry a rate of only 44-kt.). Plasma guns use gravity accelerators to fire the round (case and all), igniting the shell as it leaves the gun tube—a powerful magnetic shield generator encapsulates the plasma bolt as it exits the barrel, allowing the bolt to retain its energy for as long as two and a quarter seconds, depending on the power of the weapon itself (heavier weapons can generate stronger magnetic bottles that last for longer durations, hence they have more range, with the massive 48cms having a range of 32,500 kilometers). The magnetic shield generator matches frequencies with the ships shields (see number 8 below) so that the bolt may safely exit the shield bubble. Plasma cannons also feature a cooling system that flushes the barrel with liquid nitrogen after each shot—firing a weapon before it has cooled sufficiently risks detonation of the shell within the chamber itself (and consequently the utter destruction of the ship which suffers this catastrophe). This makes plasma cannons relatively slow firing, although smaller caliber guns are able to be cooled faster, giving lighter weapons a higher rate of fire (for example, a 35mm plasma cannon can fire one round every four seconds, while a 48cm plasma cannon is limited to one shot every one hundred and eighty seconds). Plasma bolts travel at almost 5% of light speed, meaning it takes pure luck for any point-defense system to successfully detonate a bolt before impact. While plasma cannons can be fired within an atmosphere, the density of that blanket of air greatly reduces range (even the heaviest plasma cannons seldom exceed a thousand kilometers within an atmosphere) and may cause premature detonation of the plasma bolt before impact, depending upon the exact atmospheric conditions. Light or medium caliber plasma cannons fired from orbit through a standard atmosphere (0.8 to 1.2 Earth norm) cannot reach the surface, although heavy plasma guns (23cm or larger) can. Cloud cover and precipitation can cause the magnetic containment bubble to rupture prematurely as the bolt passes through the atmospheric phenomena—making orbital bombardment with plasma cannons very much a hit or miss proposition except at the shortest ranges. Due to their ability to operate within an atmosphere, destroyers are most often the ships called upon to deliver pin-point plasma bombardment at ranges as short as 25 kilometers.
4. Mass driver cannons are an older technology, but for rapid-fire point defense there are few more effective weapon systems. Even a single shell from a mass-driver can prematurely detonate a plasma bolt (although such a hit is more a matter of luck and probability than gunnery skill), and against missiles and torpedoes they are equally devastating. While a fighter or shuttle may not be destroyed by a hit from a single round, the quad- and twin-mount mass drivers used in point-defense emplacements can often deliver dozens of hits almost simultaneously, causing heavy damage if not complete destruction.
5. For most Imperial ships, the main battery is emplaced in twin ball turrets along the flanks and/or bow of the vessel. This configuration allows the main battery to elevate and depress up to slightly more than 110-degrees positive and negative, as well as traverse as much as 120-degrees in the horizontal plane.
6. The secondary battery is situated above and below the mains, typically as much as 20 meters farther inboard from the perimeter of the ship. These guns also use twin ball turrets, but their position on the hull surface and the general shape of the hull itself does not afford them the same wide arcs of fire as the main battery (typically elevation of 120- to 150-degrees and depression of 10-degrees, with a traverse of 90- to 120-degrees for dorsal mounts, the elevation and depression are reversed for ventral mounts).
7. The point defense battery is distributed across the ship’s hull as evenly as possible to obtain the maximum defensive fire versus a threat from any vector.
8. Torpedo batteries consist of inclined launch cells built into the dorsal and ventral surfaces of the ship’s hull, positioned to fire forward. A typical Imperial warship carries a battery of torpedo cells consisting of 48 dorsal launchers and 48 ventral launchers. A standard torpedo spread is normally a dozen torpedoes launched simultaneously from both the dorsal and ventral cells (for a total of 24 torps per salvo). This gives Imperial ships a nominal load of four salvoes before depleting their onboard munitions. However, the vessel launching torpedoes can flush any number of their remaining loaded torpedo cells in single massive barrage, typically to ensure saturation of a targets defensive fire. Alternatively, torpedoes can be launched individually, which is normally the case when using these munitions for orbital bombardment. Residual radiation and fallout from the use of torpedoes against surface targets is quite high, making it uncommon for such weapons to be used against populated worlds. Torpedo cells are one-shot weapons, once their torpedo has been launched, reloading operations must be handled by either a shipyard or a dedicated ammunition ship.
9. The Nike is the most common torpedo in imperial service. This weapon measures twenty-five meters in length and has a diameter of three meters. It carries a 220-kiloton gravitic fusion warhead that is designed to detonate a fraction of a second before impact on an active shield. The warhead can also be fused for detonation at a specific programmed altitude, or upon direct impact with a solid object, which allows for the use of torpedoes against targets on a planetary surface.
10. Torpedoes move incredibly fast over the ranges that they can cover, but every second spent in flight after launch gives enemy point-defense more time to lock up the incoming projectiles and shoot them down prior to reaching attack range. This is complicated by the fact that although torpedoes have the bulk and emissions signatures of a light fighter interceptor, they do not carry shields or armor; thus even a single hit will often destroy the torpedo, or damage it so severely that the warhead will not detonate on impact. They do carry electronic warfare equipment, however, and so locking onto a torpedo—especially at close ranges with flight times of only a handful of seconds—is difficult to do. But, once again, the longer the flight time, the most likely it is that the target’s fire control and tracking systems will achieve a lock and destroy the weapon before impact.
11. Many Imperial warships are also equipped with orbital bombardment tubes along their ventral surfaces. Akin to mass drivers, these weapons accelerate a solid slug of nickel-iron or tungsten to high velocities—although they remain too slow to be used in ship-to-ship combat, except at point-blank ranges. These projectiles (also known in the naval service as ‘crowbars’) mass between ten and fifty metric tons each and are normally used to conduct orbital bombardment against entrenched defenders on a planetary surface. Given the difficulty in firing plasma bolts from orbit through a planetary atmosphere to the surface, these weapons are often the best means of precisely removing fortified positions; they are also ‘clean’ kinetic energy weapons with no residual radiation effects.
12. The main armor belt is concentrated along the flanks and bow, with the dorsal surfaces, ventral surfaces, and stern having roughly half to two-thirds the armor protection of the main belt. Additional internal plating surrounds all plasma magazines, small craft magazines, and torpedo launchers, as well as vital areas such as the CIC, bridge, flag bridge, fuel storage tanks, and engineering spaces. Modern Imperial armor is known as Hawkins-Connors Alloy and is comprised of a molecularly-aligned carbon-based ceramic compound that has the hardness of diamond, but just one-sixteenth the mass of a similar volume of steel-alloy armor plating. The (relatively) low density and mass allows Imperial designers to provide a thickness of protection heretofore unheard of—absorbing both kinetic and energy based attacks, as well as blocking alpha-, beta-, and gamma- emissions of radioactive isotopes and nuclear/plasma detonations. When struck, the hardness of the armor helps to resist kinetic penetration, while the thickness absorbs the ambient energy, sacrificing layer after layer to ablate the effects of the attack. Kinetic weapons such as point defense or fighter-based mass-drivers crater the surface of the armor, but generally cannot penetrate more than 5-30cm, depending upon the caliber of the weapon (although surface-based heavy mass drivers in the 135mm+ range used in the anti-spacecraft role cause between four and ten times this amount of damage, but have low rates of fire and are only effective when used en masse against targets very close to the planet). Generally speaking, the armor can withstand surface detonations of approximately 25-kilotons per meter of thickness, although such an attack will dramatically thin the armor by vaporizing the outer, central, and even inner layers. Shock damage to the interior of the vessel is liable to be quite high, even if the detonation did not manage to penetrate the armored hull. Imperial warships tend to be double hulled, with two layers of armor separated by a two-or-three meter thick vacuum filled void. Although this practice consumes vital internal volume, it does provide a low-cost and low-mass means of enhancing overall protection versus shock transference. Destroyers tend to have 3-5 meters of armor in their main belt, cruisers 7-12, and battleships 16 or more—with some of the heaviest and best protected dreadnoughts carrying as much as 30-meters of armor protection over their vital areas. The very nature and composition of this armor interferes with all frequencies of the electromagnetic spectrum, meaning the thicker the armor plating, the less effective sensor systems and EM based communications systems become. This has lead to the Imperial practice of incorporating a lightly armored sensor tower on all of their warships, but lighter (and less armored) vessels still retain a sizable advantage in both sensor reach and resolution. Tachyon-based short-range and interstellar communications are not affected by armor.
13. Capital warship grade shields project a ‘bubble’ around the vessel mounting them. This bubble is normally invisible to the naked eye, but visibly flares when struck by objects exceeding 100 grams in mass or by high levels of radiated energy. These shields tend to vaporize less massive objects and absorb radiated energy. They can even absorb the energy from a multi-hundred kiloton nuclear/plasma detonation at distances of 100-meters or more from the surface of the shield The gravity stresses in a shield tend to shred objects which attempt to pass through them—unless those objects are specifically tuned to the shields frequency (readers should take note: there are potentially thousands of different shield frequencies, and Imperial vessels tend to shift frequency in a random pattern controlled by the ship’s primary computer network); fighters, small craft, and torpedoes launched from a shielded vessel can penetrate the shields without incident, as well as plasma bolts and mass-driver bursts from the main, secondary, and point-defense batteries (the weapons are tuned to the current frequency when fired). Hostile torpedoes (and heavy anti-ship fighter missiles) are normally programmed to detonate just before contact with the shield surface. However, shields do have their limits—massive amounts of direct energy striking the same general location can overload the shields and create a ‘hole’ through which subsequent attacks can pass unhindered. Furthermore, very high levels of ambient energy (such as being in close proximity to a star) can weaken shields considerably, making them more susceptible to suffering localized overloads. A direct shield hit by a high yield nuclear/plasma detonation can also—in many cases—cause a feedback in the shield generators themselves, possibly knocking one or more generators off-line and leaving portions of the ship vulnerable to further attacks. Shield strength is directly related to the power a vessel is able to feed the generators; hence larger vessels tend to have stronger shields (much stronger in many cases) than lighter ones (for example, a Leviathan class battleship has shields strong enough to remain intact even with a direct contact detonation in the 200+ kiloton range, while the shields aboard an Alexander class destroyer will collapse from a single hit with one-quarter that yield). Vessels designed to operate within a planetary atmosphere and land on a planetary surface uses their shields to absorb the heat of reentry operations, protecting weapon turrets and other vital surface hull fixtures from damage—however, such vessels are extremely vulnerable to attack during this procedure, as most of their available shield strength is dedicated to protecting the ship’s hull from reentry.
14. Sub-light thrust is given in three values—sustained, flank, and emergency full. Vessels can accelerate or decelerate at their sustained thrust while retaining enough power for shields and weapons. Flank speed requires that power be diverted from the main and secondary batteries, although the shields remain functional. Emergency thrust can only be achieved by diverting power from the main battery, secondary battery, and shields—the point-defense battery and torpedo battery still retain power even at the maximum rate of acceleration possible.
15. Inertial compensators negate the effects of prolonged acceleration aboard capital warships, while gravity plates in the decks provide artificial gravity throughout the vessel.
16. FTL travel is given in light-years per hour; the maximum possible duration of a single FTL flight is 20 hours, 34 minutes, and 48 seconds—or slightly less than 68 light-years for a PSK drive with a rating of 3.3, just over 45 light-years for a drive rated at 2.2. However, the vessels of the Imperial Fleet are hard-wired for FTL transits of no longer than 12 continous hours (~40 light-years and ~26 light-years, respectively). PSK drives must spend two seconds at sub-light speeds for every second spent traveling FTL in order to ‘reset’ the maximum duration. Multiple FTL transits without a significant period between to rest the drives cause the system to fail at 20 hours, 34 minutes, and 49 seconds, disabling the ship in question.
17. Imperial vessels tend to mount a ‘sensor tower’ on their dorsal hull that extends as much as 100% above the listed ship height. This tower is very lightly armored (typically about 10% of the thickness of the main armor belt) and includes short-, medium-, and long-range sensors, tracking and targeting systems, and non-FTL communications systems. Except for a few access hatches and pressurized compartments used for maintenance, the majority of the internal volume of the sensor tower is normally kept in a hard vacuum. Due to the fragile nature of this lightly armored structure, the sensor tower is not manned during action, but instead relies upon automated systems directed by crewmen within the main armored hull. Destroying a sensor tower can reduce a ship’s sensor reach, resolution, and target tracking capability by as much as 50% on heavier vessels (approximately 20% on destroyers). Since sensor towers are protected by the ship’s shields, and shield penetrations tend to be localized around the point of heaviest damage, most warship tactical crews do not try to deliberate target this location. Furthermore, even if completely destroyed, the loss of the sensor tower does not cause significant damage to the main body of the ship itself—other than the loss of sensor capability. However, Murphy being what and who he is, damage to the sensor tower is distressingly commonplace. Fighters—on the other hand—try to damage the sensor tower as rapidly as possible, since doing so reduces the effectiveness of a warships point defense fire against them.
18. All Imperial vessels are equipped with at least a pair, sometimes as many as six, tractor/pressor generators. These units project a short-range beam of gravity that allows the ship to tow damaged vessels, pin hostile vessels in place, or move asteroids and meteors of fairly small scale.
19. All Imperial vessels are equipped with emergency escape boats able to embark at least 80% of the ship’s maximum crew and passenger complement. These escape boats are built into the hull, are covered by blow-off armored panels, and are capable of operating for up to seventy-two hours before their power supplies are depleted. Each is able to safely deorbit and conduct a non-powered reentry, using a combination of gravity drives and parachutes to soft-land on a planetary surface. The escape boats contain emergency supplies and provisions to last twenty personnel for up to two weeks. Escape boats are short-ranged craft, with only a limited ability to accelerate or decelerate, and are designed to be used just one time. Once the boats have been launched, it requires a shipyard or fleet tender to install new ones and the armor panels that cover them during normal operations.